Azo dyes



Patented Sept. 23, 1924.

UNITED STATES PATENT OFFICE.

JAMES P. PENNY, OF BUFFALO, NEW YORK, ASSIGNOR TO NATIONAL ANILINE & CHEMICAL COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

.AZO nns.

1T0 Drawing.

. To all whom it may Buffalo, in the county of Erie, State of New York, have invented certain new and useful Improvements in Azo Dyes; and I do here by declare the followi to be a full, clear, and exact description 0 the invention, such as will enable others sldlled in the art to which it appertains to make and use the same.

This invention relates to the production of new azo dyes which are of value for dyeing cotton and other vegetable fibres. The dyed fabrics, or other material, dyed with the new dyestufis also form a part of the present invention.

The new dyestufls can be obtained by'combining two molecular proportions of a diazotized aminoazosulfonic acid of the benzene series, such as diazdtized aminoazoben zenedisulfonic acid, or aminoazotoluenedisulfonic acid, with one molecular proportion of 5.5'-dihydroxy-2.2-djnaphthylurea-7 .7 disulfonic acid (i. e., symmetrical urea derivative of 2.5-amjnonaphthol-7-sulfonic acid).

The following specific example will further illustrate the invention, but it is un- Applieation filed July 13, 1922. Serial No. 574,789.

derstood that the invention is not limited thereto; The parts are by weight.

160.5 parts of the di sodium salt of 4- aminoazobenzene-l Ar'-disulfonic acid are dissolved in 1000 parts of water and diazotized in the usual manner at a temperature of about 10 C. with the aid of 130 parts hydrochloric acid of 20 B. and 28 parts of sodium nitrite. The resulting diazo solution is then stirred into a cold solution prepared by dissolving 110 parts of the sodium salt of 5.5-dihydroxy-2.2'-dinaphthylurea- 7 .7 -disulfonic acid in 1000 parts of water. Whilst stirring the mixture, which is maintained at a temperature of about 15 0.,

there is slowly and gradually added a strong aqueous solution of sodium carbonate until the mixture gives an alkaline reaction toward brilliant yellow test paper and a test portion of the mixture no longer reacts with R-salt to give a brownish-red coloration. The amount of sodium carbonate usually required is about 200 parts. After stirring the solution for about an hour, the dye is salted out by the addition of common salt, filtered ofi', dried, and ground to a powder.

The new dyestufl' thus obtained is the sodium salt of an acid having most prob ably the following formula:

and in the dry and pulverized state is a reddish-brown powder soluble in water with a crimson color, soluble in concentrated sul furic acid with a greenish-blue color which upon dilution with water changes to a crim son color, and soluble in concentrated hydrochloric acid with a reddish-violet color. The new dyestufi directly dyes coltton bluish red shades which are of excellent fastness to acids, to alkalies and to light, and which are capable of being discharged to a white with hydrosulfite. In a neutral Glaubers salt bath, it dyes cotton but leaves wool and silk almost unstained; in an acid bath it dyes silk and wool.

If in the above example, the aminoazobenzene disulfonic acid isreplaced by an equivalent quantit of 2.3'-dimethyl-4'-aminoazobenzene disu fonic acid, which maybe obtained b the direct sulfonation of 2.3-

dimeithyl-4 -aminoazobenzene, there is produced a dyestuif which dyes cotton consider ably bluer shades, and in a neutral Glaubers salt bath leaves wool and silk almost unstained. It (1 es silk and wool in an acid bath. In the ry state it is a brownish powder soluble in water with a crimson color and in concentrated sulfuric acid with a bluish green color.

I claim:

1. The hereindescribed new azo dyestuifs acid, which shades, leaving wool and silk almost entirely 2. The hereindescribed new 2120 dyestuif unstained, and being discharged to a white being the alkaline salt of an acid having 5 with hydrosulfite, most probably the following formula:

which in the dry and pulverized state and bath to the almost entire exclusion of wool in the shape of 1ts sodium'salt is a. reddish or silk, and capable of being discharged with brown powder soluble in water with a crimhydrosulfite.

10 son color, soluble in concentrated sulfuric 3. Materials with the new azo dyestuffs of acid with a greenish blue color which upon claim 1. 20 dilution with water changes to a crimson 4. Materials dyed with the new azo dyecolor, soluble in concentrated hydrochloric stuff of claim 2.

acid with a reddish violet color; and dyeing In testimony whereof I affix my signature. 1 unmordanted cotton red shades in a neutral JAMES P. PENNY. 

